ssize_t send(int sockfd, const void *buf, size_t len, int flags)
{
FAR struct socket *psock = sockfd_socket(sockfd);
struct send_s state;
uip_lock_t save;
int err;
int ret = OK;
/* Verify that the sockfd corresponds to valid, allocated socket */
if (!psock || psock->s_crefs <= 0)
{
err = EBADF;
goto errout;
}
/* If this is an un-connected socket, then return ENOTCONN */
if (psock->s_type != SOCK_STREAM || !_SS_ISCONNECTED(psock->s_flags))
{
err = ENOTCONN;
goto errout;
}
/* Set the socket state to sending */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_SEND);
/* Perform the TCP send operation */
/* Initialize the state structure. This is done with interrupts
* disabled because we don't want anything to happen until we
* are ready.
*/
save = uip_lock();
memset(&state, 0, sizeof(struct send_s));
(void)sem_init(&state. snd_sem, 0, 0); /* Doesn't really fail */
state.snd_sock = psock; /* Socket descriptor to use */
state.snd_buflen = len; /* Number of bytes to send */
state.snd_buffer = buf; /* Buffer to send from */
if (len > 0)
{
struct uip_conn *conn = (struct uip_conn*)psock->s_conn;
/* Allocate resources to receive a callback */
state.snd_cb = uip_tcpcallbackalloc(conn);
if (state.snd_cb)
{
/* Get the initial sequence number that will be used */
state.snd_isn = uip_tcpgetsequence(conn->sndseq);
/* There is no outstanding, unacknowledged data after this
* initial sequence number.
*/
conn->unacked = 0;
/* Update the initial time for calculating timeouts */
#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
state.snd_time = clock_systimer();
#endif
/* Set up the callback in the connection */
state.snd_cb->flags = UIP_ACKDATA|UIP_REXMIT|UIP_POLL|UIP_CLOSE|UIP_ABORT|UIP_TIMEDOUT;
state.snd_cb->priv = (void*)&state;
state.snd_cb->event = send_interrupt;
/* Notify the device driver of the availaibilty of TX data */
netdev_txnotify(&conn->ripaddr);
/* Wait for the send to complete or an error to occur: NOTES: (1)
* uip_lockedwait will also terminate if a signal is received, (2) interrupts
* may be disabled! They will be re-enabled while the task sleeps and
* automatically re-enabled when the task restarts.
*/
ret = uip_lockedwait(&state. snd_sem);
/* Make sure that no further interrupts are processed */
uip_tcpcallbackfree(conn, state.snd_cb);
}
}
sem_destroy(&state. snd_sem);
uip_unlock(save);
/* Set the socket state to idle */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_IDLE);
/* Check for a errors. Errors are signaled by negative errno values
* for the send length
*/
if (state.snd_sent < 0)
{
err = state.snd_sent;
goto errout;
}
/* If uip_lockedwait failed, then we were probably reawakened by a signal. In
* this case, uip_lockedwait will have set errno appropriately.
*/
if (ret < 0)
{
err = -ret;
goto errout;
}
/* Return the number of bytes actually sent */
return state.snd_sent;
errout:
*get_errno_ptr() = err;
return ERROR;
}
static uint16_t send_interrupt(FAR struct uip_driver_s *dev, FAR void *pvconn,
FAR void *pvpriv, uint16_t flags)
{
FAR struct uip_conn *conn = (FAR struct uip_conn*)pvconn;
FAR struct socket *psock = (FAR struct socket *)pvpriv;
nllvdbg("flags: %04x\n", flags);
/* If this packet contains an acknowledgement, then update the count of
* acknowledged bytes.
*/
if ((flags & UIP_ACKDATA) != 0)
{
FAR sq_entry_t *entry, *next;
FAR struct uip_wrbuffer_s *segment;
uint32_t ackno;
ackno = uip_tcpgetsequence(TCPBUF->ackno);
for (entry = sq_peek(&conn->unacked_q); entry; entry = next)
{
next = sq_next(entry);
segment = (FAR struct uip_wrbuffer_s*)entry;
if (segment->wb_seqno < ackno)
{
nllvdbg("ACK: acked=%d buflen=%d ackno=%d\n",
segment->wb_seqno, segment->wb_nbytes, ackno);
/* Segment was ACKed. Remove from ACK waiting queue */
sq_rem(entry, &conn->unacked_q);
/* Return the write buffer to the pool of free buffers */
uip_tcpwrbuffer_release(segment);
}
}
}
/* Check for a loss of connection */
else if ((flags & (UIP_CLOSE | UIP_ABORT | UIP_TIMEDOUT)) != 0)
{
/* Report not connected */
nllvdbg("Lost connection\n");
net_lostconnection(psock, flags);
goto end_wait;
}
/* Check if we are being asked to retransmit data */
else if ((flags & UIP_REXMIT) != 0)
{
sq_entry_t *entry;
/* Put all segments that have been sent but not ACKed to write queue
* again note, the un-ACKed segment is put at the first of the write_q,
* so it can be sent as soon as possible.
*/
while ((entry = sq_remlast(&conn->unacked_q)))
{
struct uip_wrbuffer_s *segment = (struct uip_wrbuffer_s*)entry;
if (segment->wb_nrtx >= UIP_MAXRTX)
{
//conn->unacked -= segment->wb_nbytes;
/* Return the write buffer */
uip_tcpwrbuffer_release(segment);
/* NOTE expired is different from un-ACKed, it is designed to
* represent the number of segments that have been sent,
* retransmitted, and un-ACKed, if expired is not zero, the
* connection will be closed.
*
* field expired can only be updated at UIP_ESTABLISHED state
*/
conn->expired++;
continue;
}
send_insert_seqment(segment, &conn->write_q);
}
}
/* Check if the outgoing packet is available (it may have been claimed
* by a sendto interrupt serving a different thread).
*/
if (dev->d_sndlen > 0)
{
/* Another thread has beat us sending data, wait for the next poll */
return flags;
}
/* We get here if (1) not all of the data has been ACKed, (2) we have been
* asked to retransmit data, (3) the connection is still healthy, and (4)
* the outgoing packet is available for our use. In this case, we are
* now free to send more data to receiver -- UNLESS the buffer contains
* unprocesed incoming data. In that event, we will have to wait for the
* next polling cycle.
*/
if ((conn->tcpstateflags & UIP_ESTABLISHED) &&
(flags & (UIP_POLL | UIP_REXMIT)) &&
!(sq_empty(&conn->write_q)))
{
/* Check if the destination IP address is in the ARP table. If not,
* then the send won't actually make it out... it will be replaced with
* an ARP request.
*
* NOTE 1: This could be an expensive check if there are a lot of
* entries in the ARP table.
*
* NOTE 2: If we are actually harvesting IP addresses on incomming IP
* packets, then this check should not be necessary; the MAC mapping
* should already be in the ARP table.
*/
#if defined(CONFIG_NET_ETHERNET) && !defined(CONFIG_NET_ARP_IPIN)
if (uip_arp_find(conn->ripaddr) != NULL)
#endif
{
FAR struct uip_wrbuffer_s *segment;
FAR void *sndbuf;
size_t sndlen;
/* Get the amount of data that we can send in the next packet */
segment = (FAR struct uip_wrbuffer_s *)sq_remfirst(&conn->write_q);
if (segment)
{
sndbuf = segment->wb_buffer;
sndlen = segment->wb_nbytes;
DEBUGASSERT(sndlen <= uip_mss(conn));
/* REVISIT: There should be a check here to assure that we do
* not excced the window (conn->winsize).
*/
/* Set the sequence number for this segment. NOTE: uIP
* updates sndseq on receipt of ACK *before* this function
* is called. In that case sndseq will point to the next
* unacknowledged byte (which might have already been
* sent). We will overwrite the value of sndseq here
* before the packet is sent.
*/
if (segment->wb_nrtx == 0 && segment->wb_seqno == (unsigned)-1)
{
segment->wb_seqno = conn->isn + conn->sent;
}
uip_tcpsetsequence(conn->sndseq, segment->wb_seqno);
/* Then set-up to send that amount of data. (this won't
* actually happen until the polling cycle completes).
*/
uip_send(dev, sndbuf, sndlen);
/* Remember how much data we send out now so that we know
* when everything has been acknowledged. Just increment
* the amount of data sent. This will be needed in
* sequence* number calculations and we know that this is
* not a re-transmission. Re-transmissions do not go through
* this path.
*/
if (segment->wb_nrtx == 0)
{
conn->unacked += sndlen;
conn->sent += sndlen;
}
/* Increment the retransmission counter before expiration.
* NOTE we will not calculate the retransmission timer
* (RTT) to save cpu cycles, each send_insert_seqment
* segment will be retransmitted UIP_MAXRTX times in halt-
* second interval before expiration.
*/
segment->wb_nrtx++;
/* The segment is waiting for ACK again */
send_insert_seqment(segment, &conn->unacked_q);
/* Only one data can be sent by low level driver at once,
* tell the caller stop polling the other connection.
*/
flags &= ~UIP_POLL;
}
}
}
/* Continue waiting */
return flags;
end_wait:
/* Do not allow any further callbacks */
psock->s_sndcb->flags = 0;
psock->s_sndcb->event = NULL;
return flags;
}
static uint16_t send_interrupt(struct uip_driver_s *dev, void *pvconn,
void *pvpriv, uint16_t flags)
{
struct uip_conn *conn = (struct uip_conn*)pvconn;
struct send_s *pstate = (struct send_s *)pvpriv;
nllvdbg("flags: %04x acked: %d sent: %d\n",
flags, pstate->snd_acked, pstate->snd_sent);
/* If this packet contains an acknowledgement, then update the count of
* acknowldged bytes.
*/
if ((flags & UIP_ACKDATA) != 0)
{
/* The current acknowledgement number number is the (relative) offset
* of the of the next byte needed by the receiver. The snd_isn is the
* offset of the first byte to send to the receiver. The difference
* is the number of bytes to be acknowledged.
*/
pstate->snd_acked = uip_tcpgetsequence(TCPBUF->ackno) - pstate->snd_isn;
nllvdbg("ACK: acked=%d sent=%d buflen=%d\n",
pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen);
/* Have all of the bytes in the buffer been sent and acknowledged? */
if (pstate->snd_acked >= pstate->snd_buflen)
{
/* Yes. Then pstate->snd_buflen should hold the number of bytes
* actually sent.
*/
goto end_wait;
}
/* No.. fall through to send more data if necessary */
}
/* Check if we are being asked to retransmit data */
else if ((flags & UIP_REXMIT) != 0)
{
/* Yes.. in this case, reset the number of bytes that have been sent
* to the number of bytes that have been ACKed.
*/
pstate->snd_sent = pstate->snd_acked;
/* Fall through to re-send data from the last that was ACKed */
}
/* Check for a loss of connection */
else if ((flags & (UIP_CLOSE|UIP_ABORT|UIP_TIMEDOUT)) != 0)
{
/* Report not connected */
nllvdbg("Lost connection\n");
pstate->snd_sent = -ENOTCONN;
goto end_wait;
}
/* Check if the outgoing packet is available (it may have been claimed
* by a sendto interrupt serving a different thread).
*/
#if 0 /* We can't really support multiple senders on the same TCP socket */
else if (dev->d_sndlen > 0)
{
/* Another thread has beat us sending data, wait for the next poll */
return flags;
}
#endif
/* We get here if (1) not all of the data has been ACKed, (2) we have been
* asked to retransmit data, (3) the connection is still healthy, and (4)
* the outgoing packet is available for our use. In this case, we are
* now free to send more data to receiver -- UNLESS the buffer contains
* unprocessing incoming data. In that event, we will have to wait for the
* next polling cycle.
*/
if ((flags & UIP_NEWDATA) == 0 && pstate->snd_sent < pstate->snd_buflen)
{
uint32_t seqno;
/* Get the amount of data that we can send in the next packet */
uint32_t sndlen = pstate->snd_buflen - pstate->snd_sent;
if (sndlen > uip_mss(conn))
{
sndlen = uip_mss(conn);
}
/* Set the sequence number for this packet. NOTE: uIP updates
* sndseq on recept of ACK *before* this function is called. In that
* case sndseq will point to the next unacknowledge byte (which might
* have already been sent). We will overwrite the value of sndseq
* here before the packet is sent.
*/
seqno = pstate->snd_sent + pstate->snd_isn;
nllvdbg("SEND: sndseq %08x->%08x\n", conn->sndseq, seqno);
uip_tcpsetsequence(conn->sndseq, seqno);
/* Then set-up to send that amount of data. (this won't actually
* happen until the polling cycle completes).
*/
uip_send(dev, &pstate->snd_buffer[pstate->snd_sent], sndlen);
/* Check if the destination IP address is in the ARP table. If not,
* then the send won't actually make it out... it will be replaced with
* an ARP request.
*
* NOTE 1: This could an expensive check if there are a lot of entries
* in the ARP table. Hence, we only check on the first packet -- when
* snd_sent is zero.
*
* NOTE 2: If we are actually harvesting IP addresses on incomming IP
* packets, then this check should not be necessary; the MAC mapping
* should already be in the ARP table.
*/
#if defined(CONFIG_NET_ETHERNET) && defined (CONFIG_NET_ARP_IPIN)
if (pstate->snd_sent != 0 || uip_arp_find(conn->ripaddr) != NULL)
#endif
{
/* Update the amount of data sent (but not necessarily ACKed) */
pstate->snd_sent += sndlen;
nllvdbg("SEND: acked=%d sent=%d buflen=%d\n",
pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen);
/* Update the send time */
#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
pstate->snd_time = clock_systimer();
#endif
}
}
/* All data has been send and we are just waiting for ACK or re-transmit
* indications to complete the send. Check for a timeout.
*/
#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
else if (send_timeout(pstate))
{
/* Yes.. report the timeout */
nlldbg("SEND timeout\n");
pstate->snd_sent = -ETIMEDOUT;
goto end_wait;
}
#endif /* CONFIG_NET_SOCKOPTS && !CONFIG_DISABLE_CLOCK */
/* Continue waiting */
return flags;
end_wait:
/* Do not allow any further callbacks */
pstate->snd_cb->flags = 0;
pstate->snd_cb->priv = NULL;
pstate->snd_cb->event = NULL;
/* There are no outstanding, unacknowledged bytes */
conn->unacked = 0;
/* Wake up the waiting thread */
sem_post(&pstate->snd_sem);
return flags;
}
static uint16_t send_interrupt(FAR struct uip_driver_s *dev, FAR void *pvconn,
FAR void *pvpriv, uint16_t flags)
{
FAR struct uip_conn *conn = (FAR struct uip_conn*)pvconn;
FAR struct send_s *pstate = (FAR struct send_s *)pvpriv;
nllvdbg("flags: %04x acked: %d sent: %d\n",
flags, pstate->snd_acked, pstate->snd_sent);
/* If this packet contains an acknowledgement, then update the count of
* acknowledged bytes.
*/
if ((flags & UIP_ACKDATA) != 0)
{
/* Update the timeout */
#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
pstate->snd_time = clock_systimer();
#endif
/* The current acknowledgement number number is the (relative) offset
* of the of the next byte needed by the receiver. The snd_isn is the
* offset of the first byte to send to the receiver. The difference
* is the number of bytes to be acknowledged.
*/
pstate->snd_acked = uip_tcpgetsequence(TCPBUF->ackno) - pstate->snd_isn;
nllvdbg("ACK: acked=%d sent=%d buflen=%d\n",
pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen);
/* Have all of the bytes in the buffer been sent and acknowledged? */
if (pstate->snd_acked >= pstate->snd_buflen)
{
/* Yes. Then pstate->snd_buflen should hold the number of bytes
* actually sent.
*/
goto end_wait;
}
/* No.. fall through to send more data if necessary */
}
/* Check if we are being asked to retransmit data */
else if ((flags & UIP_REXMIT) != 0)
{
/* Yes.. in this case, reset the number of bytes that have been sent
* to the number of bytes that have been ACKed.
*/
pstate->snd_sent = pstate->snd_acked;
#if defined(CONFIG_NET_TCP_SPLIT)
/* Reset the even/odd indicator to even since we need to
* retransmit.
*/
pstate->snd_odd = false;
#endif
/* Fall through to re-send data from the last that was ACKed */
}
/* Check for a loss of connection */
else if ((flags & (UIP_CLOSE|UIP_ABORT|UIP_TIMEDOUT)) != 0)
{
/* Report not connected */
nllvdbg("Lost connection\n");
net_lostconnection(pstate->snd_sock, flags);
pstate->snd_sent = -ENOTCONN;
goto end_wait;
}
/* Check if the outgoing packet is available (it may have been claimed
* by a sendto interrupt serving a different thread).
*/
#if 0 /* We can't really support multiple senders on the same TCP socket */
else if (dev->d_sndlen > 0)
{
/* Another thread has beat us sending data, wait for the next poll */
return flags;
}
#endif
/* We get here if (1) not all of the data has been ACKed, (2) we have been
* asked to retransmit data, (3) the connection is still healthy, and (4)
* the outgoing packet is available for our use. In this case, we are
* now free to send more data to receiver -- UNLESS the buffer contains
* unprocessed incoming data. In that event, we will have to wait for the
* next polling cycle.
*/
if ((flags & UIP_NEWDATA) == 0 && pstate->snd_sent < pstate->snd_buflen)
{
uint32_t seqno;
/* Get the amount of data that we can send in the next packet */
uint32_t sndlen = pstate->snd_buflen - pstate->snd_sent;
#if defined(CONFIG_NET_TCP_SPLIT)
/* RFC 1122 states that a host may delay ACKing for up to 500ms but
* must respond to every second segment). This logic here will trick
* the RFC 1122 recipient into responding sooner. This logic will be
* activated if:
*
* 1. An even number of packets has been send (where zero is an even
* number),
* 2. There is more data be sent (more than or equal to
* CONFIG_NET_TCP_SPLIT_SIZE), but
* 3. Not enough data for two packets.
*
* Then we will split the remaining, single packet into two partial
* packets. This will stimulate the RFC 1122 peer to ACK sooner.
*
* Don't try to split very small packets (less than CONFIG_NET_TCP_SPLIT_SIZE).
* Only the first even packet and the last odd packets could have
* sndlen less than CONFIG_NET_TCP_SPLIT_SIZE. The value of sndlen on
* the last even packet is guaranteed to be at least MSS/2 by the
* logic below.
*/
if (sndlen >= CONFIG_NET_TCP_SPLIT_SIZE)
{
/* sndlen is the number of bytes remaining to be sent.
* uip_mss(conn) will return the number of bytes that can sent
* in one packet. The difference, then, is the number of bytes
* that would be sent in the next packet after this one.
*/
int32_t next_sndlen = sndlen - uip_mss(conn);
/* Is this the even packet in the packet pair transaction? */
if (!pstate->snd_odd)
{
/* next_sndlen <= 0 means that the entire remaining data
* could fit into this single packet. This is condition
* in which we must do the split.
*/
if (next_sndlen <= 0)
{
/* Split so that there will be an odd packet. Here
* we know that 0 < sndlen <= MSS
*/
sndlen = (sndlen / 2) + 1;
}
}
/* No... this is the odd packet in the packet pair transaction */
else
{
/* Will there be another (even) packet afer this one?
* (next_sndlen > 0) Will the split condition occur on that
* next, even packet? ((next_sndlen - uip_mss(conn)) < 0) If
* so, then perform the split now to avoid the case where the
* byte count is less than CONFIG_NET_TCP_SPLIT_SIZE on the
* next pair.
*/
if (next_sndlen > 0 && (next_sndlen - uip_mss(conn)) < 0)
{
/* Here, we know that sndlen must be MSS < sndlen <= 2*MSS
* and so (sndlen / 2) is <= MSS.
*/
sndlen /= 2;
}
}
}
/* Toggle the even/odd indicator */
pstate->snd_odd ^= true;
#endif /* CONFIG_NET_TCP_SPLIT */
if (sndlen > uip_mss(conn))
{
sndlen = uip_mss(conn);
}
/* Check if we have "space" in the window */
if ((pstate->snd_sent - pstate->snd_acked + sndlen) < conn->winsize)
{
/* Set the sequence number for this packet. NOTE: uIP updates
* sndseq on recept of ACK *before* this function is called. In that
* case sndseq will point to the next unacknowledged byte (which might
* have already been sent). We will overwrite the value of sndseq
* here before the packet is sent.
*/
seqno = pstate->snd_sent + pstate->snd_isn;
nllvdbg("SEND: sndseq %08x->%08x\n", conn->sndseq, seqno);
uip_tcpsetsequence(conn->sndseq, seqno);
/* Then set-up to send that amount of data. (this won't actually
* happen until the polling cycle completes).
*/
uip_send(dev, &pstate->snd_buffer[pstate->snd_sent], sndlen);
/* Check if the destination IP address is in the ARP table. If not,
* then the send won't actually make it out... it will be replaced with
* an ARP request.
*
* NOTE 1: This could be an expensive check if there are a lot of entries
* in the ARP table. Hence, we only check on the first packet -- when
* snd_sent is zero.
*
* NOTE 2: If we are actually harvesting IP addresses on incoming IP
* packets, then this check should not be necessary; the MAC mapping
* should already be in the ARP table.
*/
#if defined(CONFIG_NET_ETHERNET) && !defined(CONFIG_NET_ARP_IPIN)
if (pstate->snd_sent != 0 || uip_arp_find(conn->ripaddr) != NULL)
#endif
{
/* Update the amount of data sent (but not necessarily ACKed) */
pstate->snd_sent += sndlen;
nllvdbg("SEND: acked=%d sent=%d buflen=%d\n",
pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen);
}
}
}
/* All data has been sent and we are just waiting for ACK or re-transmit
* indications to complete the send. Check for a timeout.
*/
#if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK)
if (send_timeout(pstate))
{
/* Yes.. report the timeout */
nlldbg("SEND timeout\n");
pstate->snd_sent = -ETIMEDOUT;
goto end_wait;
}
#endif /* CONFIG_NET_SOCKOPTS && !CONFIG_DISABLE_CLOCK */
/* Continue waiting */
return flags;
end_wait:
/* Do not allow any further callbacks */
pstate->snd_cb->flags = 0;
pstate->snd_cb->priv = NULL;
pstate->snd_cb->event = NULL;
/* There are no outstanding, unacknowledged bytes */
conn->unacked = 0;
/* Wake up the waiting thread */
sem_post(&pstate->snd_sem);
return flags;
}
